RESUMEN

Bacterial strain M47C3B(T) was isolated from the endophytic microbial community of a Pinus pinaster tree branch from a mixed grove of pines. Phylogenetic analysis of 16S rRNA gene sequences showed that this organism represented one distinct branch within the family Sphingobacteriaceae, most closely related to the genus Mucilaginibacter. Strain M47C3B(T) formed a distinct lineage, closely related to Mucilaginibacter dorajii KACC 14556(T), with which it shared 97.2% 16S rRNA gene sequence similarity. The other members of the genus Mucilaginibacter included in the same clade were Mucilaginibacter lappiensis ATCC BAA-1855(T) sharing 97.0% similarity and Mucilaginibacter composti TR6-03(T) that had a lower similarity (95.7%). The novel strain was Gram-staining-negative, formed rod-shaped cells, grew optimally at 26 °C and at pH 7, and was able to grow with up to 0.3% (w/v) NaCl. The respiratory quinone was menaquinone 7 (MK-7) and the major fatty acids of the strain were summed feature 3 (C16 : 1ω7c/iso-C15 : 0 2-OH), iso-C15 : 0 and iso-C17 : 0 3-OH, representing 73.5% of the total fatty acids. The major components of the polar lipid profile of strain M47C3B(T) consisted of phosphatidylethanolamine, three unidentified aminophospholipids, one unidentified aminolipid and three unidentified polar lipids. The G+C content of the DNA was 40.6 mol%. On the basis of the phylogenetic analysis and physiological and biochemical characteristics we propose the name Mucilaginibacter pineti sp. nov. for the novel species represented by strain M47C3B(T) ( = CIP 110632(T) = LMG 28160(T)).

Asunto(s)

Bacteroidetes/clasificación , Filogenia , Pinus/microbiología , Madera/microbiología , Técnicas de Tipificación Bacteriana , Bacteroidetes/genética , Bacteroidetes/aislamiento & purificación , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Datos de Secuencia Molecular , Portugal , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Vitamina K 2/análogos & derivados , Vitamina K 2/química

RESUMEN

Bacterial strain A37T2(T) was isolated from the endophytic microbial community of a Pinus pinaster tree trunk and characterized. Strain A37T2(T) was Gram-stain-negative, formed rod-shaped cells, and grew optimally at 26-30 °C and at pH 5.5-7.5. The G+C content of the DNA was 46.6 mol%. The major respiratory quinone was menaquinone 7 (MK-7) and the major fatty acids were C16 : 1ω5c and iso-C15 : 0, representing 61.7 % of the total fatty acids. The polar lipids consisted of phosphatidylethanolamine, four unidentified aminophospholipids, one unidentified phospholipid, two unidentified aminolipids and three unidentified lipids. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain A37T2(T) belonged to the family Chitinophagaceae, forming a distinct branch with Chitinophaga niabensis JS13-10(T) within the genus Chitinophaga. Strain A37T2(T) shared between 92.7 and 95.1 % 16S rRNA gene sequence similarity with the type strains of species of the genus Chitinophaga. The phylogenetic, phenotypic and chemotaxonomic data presented indicate that strain A37T2(T) represents a novel species of the genus Chitinophaga, for which the name Chitinophaga costaii sp. nov. is proposed. The type strain is A37T2(T) ( = CIP 110584(T) = LMG 27458(T)). An emended description of Chitinophaga niabensis JS13-10(T) is also proposed.

Asunto(s)

Bacteroidetes/clasificación , Filogenia , Pinus/microbiología , Técnicas de Tipificación Bacteriana , Bacteroidetes/genética , Bacteroidetes/aislamiento & purificación , Composición de Base , ADN Bacteriano/genética , Endófitos/clasificación , Endófitos/genética , Endófitos/aislamiento & purificación , Ácidos Grasos/química , Datos de Secuencia Molecular , Fosfolípidos/química , Corteza de la Planta/microbiología , Portugal , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Vitamina K 2/análogos & derivados , Vitamina K 2/química

RESUMEN

A mannosylglycerate synthase (MgS) gene detected in the genome of Selaginella moellendorffii was expressed in E. coli and the recombinant enzyme was purified and characterized. A remarkable and unprecedented feature of this enzyme was the ability to efficiently synthesize mannosylglycerate (MG) and glucosylglycerate (GG) alike, with maximal activity at 50 °C, pH 8.0 and with Mg(2+) as reaction enhancer. We have also identified a novel glycoside hydrolase gene in this plant's genome, which was functionally confirmed to be highly specific for the hydrolysis of MG and GG and named MG hydrolase (MgH), due to its homology with bacterial MgHs. The recombinant enzyme was maximally active at 40 °C and at pH 6.0-6.5. The activity was independent of cations, but Mn(2+) was a strong stimulator. Regardless of these efficient enzymatic resources we could not detect MG or GG in S. moellendorffii or in the extracts of five additional Selaginella species. Herein, we describe the properties of the first eukaryotic enzymes for the synthesis and hydrolysis of the compatible solutes, MG and GG.

Asunto(s)

Ácidos Glicéricos/metabolismo , Manosa/análogos & derivados , Selaginellaceae/enzimología , Genes de Plantas , Concentración de Iones de Hidrógeno , Hidrólisis , Cinética , Espectroscopía de Resonancia Magnética , Manosa/biosíntesis , Manosiltransferasas/genética , Proteínas Recombinantes/metabolismo , Selaginellaceae/genética , Análisis de Secuencia de Proteína , Especificidad de la Especie , Temperatura